L322 (Not your usual) battery drain

I've had a search around here and I can only seem to find similar issues when it's more of a parasitic drain. My car however seems to have a huge current draw when the ignition is switched on so I'm wondering if any of you have seen this yourselves.

Sorry, this will be a long post to explain but will hopefully stop the usual questions coming out so please bear with:

2009 '59 (2010 facelift) 3.6TDV8 Vogue L322

I have an issue with my fuel burning heater which is how I actually found I have this problem, let me explain a bit further. To set the scene, I was attempting to prime the fuel pump on the FBH when I realised that every single module in my car is in fault in a big way. I have power issues and I can't clear the faults as the voltage is too low with the ignition on. This happens with FBH disconnected too so we can ignore that as a potential cause.

When I bought the car just over a year ago, the first job I did was replace the battery and it has been fine since. The battery that was in it was only about 5 months old so I kept it and that is still fine too. I've tested both batteries, the fault exists with either fitted and with a battery tester they show 87% and 84% health which is a Pass/Good reading so I can't get one replaced under warranty. I'm not ruling out the battery but to be honest, I don't want to fit yet another one just yet.

The battery DOES NOT go flat and the car always starts on the button even if left parked for a couple of weeks so it's not the usual parasitic drain.
I've checked for water ingress as we all almost need gills after the October we've had and it all seems to be dry inside which is good news too however, I haven't disconnected the amp etc. just yet. I think this usually causes the parasitic drain and as far as I can tell it is all working nicely.
I cannot find anything at all that is not operational in the car (save for FBH already ruled out).
If I take the battery off charge it will show around 12.8v and the tester confirmed circa 820 CCA for a 900CCA battery so about 87% health (figures from memory).
The car is asleep, bonnet open and the battery remains at 12.8v. Turn on the ignition and the voltage plummets to around 11.7v! This is before you try to start it and as far as I am aware, the glow plugs aren't live as it is a 2010 and only when you have your foot on the brake and push the button does it go through it's "Cold start in progress, please wait" routine and then fire up. Incidentally, it fires up with no issue every single time.



I have just about every module in fault though and one clue to it being voltage related is that every time I start the car the same track starts playing on the stereo as it resets the unit and requests the first one in the list from my phone (Acquainted by The Weekend if you're interested). On top of that, it is a matter of 2-3 minutes at a guess with the ignition on before the radio displays "Low Power" and shuts down even on a fully charged battery. If the stereo reset is a clue I can pinpoint the time this failure occurred to the time Apple released iOS 17 several weeks back as that is when I noticed that my playlists weren't continuing and put it down to a stupid bug in a new iOS release (Android users need not pipe up at this point, we all know your feelings ).

As you can see from the screenshot from GapIID, according to the car, it's basket case and everything is broken.
Ignition on:


Running:


The keen-eyed amongst you here will note that 12.2v is not good for a running car and it did increase to about 13v which again is rubbish. My first thought was that the alternator was failing and drawing down with the ignition on so I changed it last weekend and treated the car to a new aux belt etc. while I was there.

The result? It now charges at around 14.5v but the draw is the same when the engine isn't running.

So far, I have tried:
2x batteries
2x multimeters (plus 3x different diagnostic tools (because I have them available)
2x battery testers
Using an HGV jump lead as an additional earth point and trying different areas to see if it was engine to body or body to battery.
Cleaning and inspecting the earth connection to the body
Cleaning the battery terminals and cables.
Disconnecting the fuel burning heater (I had to remove it to repair it).

Oh and then the bonnet release cable snapped when I tried to check the coolant the day after fitting the new alternator, I replaced that at lunch today.

My next steps are to start pulling fuses to see what is kicking the sh*t out of the battery I guess. Ideally I would put an ammeter in place to see the real current drop but I fear that my 10a multimeter will melt if I try that! I expect I'll need both batteries on jump leads to keep the power as long as I'll need it to diagnose the issue too.

I'm interested to know your thoughts and if you have ever experienced this, ideally I'd like it to be an amplifier or whatever but do they usually continue to work when faulty like this? I'd expect it to not work or behave erratically at least.

Tomorrow I am going to drive it from Maidstone to Chesterfield, come back on Friday and then go to Plymouth Saturday and come back Sunday so I expect that will break it properly and then at least I'll know what it was or at the very least which end of the car it was that started the fire?!?!? I could take my Mustang but guess what... the battery is knackered and the new one will be delivered tomorrow after I leave or I could take my '90s C43 but even the glass rusts on those Mercs so I expect it will dissolve over that distance in salt. FML!

Hi Blob,
have you reset the ECM back to factory setting?
it sounds it could be faultyAlternator or Starter motor.
my car at one time was like that showing multiple faults.
I disconnected the bartery left it half hour then used a 1ohm 10w ceramic resistor clipped between pos & negative terminals left it half hour and ECM was back to factory settings .
my car has keyless entry if you have this bear in mind the fob will still hold incorrect data but if you drive for a few miles it should re learn .
another big problem I one encountered was a burnt out final stage resistor behind the HVAC on top of the transmission tunnel.
that was dash out Job to replace the blower motor Which was seized . Hope this may be of help
good luck Bob.

Bobbyjust said:

Hi Blob,
have you reset the ECM back to factory setting?
it sounds it could be faultyAlternator or Starter motor.
my car at one time was like that showing multiple faults.
I disconnected the bartery left it half hour then used a 1ohm 10w ceramic resistor clipped between pos & negative terminals left it half hour and ECM was back to factory settings .
my car has keyless entry if you have this bear in mind the fob will still hold incorrect data but if you drive for a few miles it should re learn .
another big problem I one encountered was a burnt out final stage resistor behind the HVAC on top of the transmission tunnel.
that was dash out Job to replace the blower motor Which was seized . Hope this may be of help
good luck Bob.

Click to expand...

me too... battery as flat as a witch's boobs...resistor is on order in turn this has also shagged the climate control panel...looking at alternatives as the original units were prone to faults...

As soon as you open the door, so the ecus fire up in preparation to start, this can be around 35A if i recall. I'll measure in the morning

didn't help matters that the original battery that was on the car was shot (which i replaced) it was then the brand new battery that went as flat as a pan cake. All this not helped by the ominous smell of burnt electronics,(being the climate control module).
I replaced that with another unit about 8 months ago which had done the same thing. everything appeared to be hunky dory until now. so at the moment the connections to said unit have been removed (with the exception of one which stops the rear blower from operating while driving) I'm probably stabbing in the dark with the hedgehog, but all reading tends to point to that resistor as the issue and i'm am assuming that this in turn has lead to the CC unit burning out...I hope!
I am now stuck looking at the original CC unit (JFC000374PUY) or going for the 2006 onwards (JFC500580LZL) which appears to have the same plug/socket arrangement. Don't really want to waste cash on buying something that's not going to cut the mustard, but i do work on the assumption that if it looks like a duck etc... Any suggestions that you may have would be really appreciated though BTW gap tool does say that i have an issue with the a/c relay giving a fault to earth...

My issues were resolved in this thread, sorry, I thought I'd closed this down but obviously not. Should have updated it but I have given myself a stern talking to about it now. https://www.landyzone.co.uk/land-ro...ult-where-to-start.389750/page-4#post-5650424

Bobbyjust said:

Hi Blob,
have you reset the ECM back to factory setting?
it sounds it could be faultyAlternator or Starter motor.
my car at one time was like that showing multiple faults.
I disconnected the bartery left it half hour then used a 1ohm 10w ceramic resistor clipped between pos & negative terminals left it half hour and ECM was back to factory settings .
my car has keyless entry if you have this bear in mind the fob will still hold incorrect data but if you drive for a few miles it should re learn .
another big problem I one encountered was a burnt out final stage resistor behind the HVAC on top of the transmission tunnel.
that was dash out Job to replace the blower motor Which was seized . Hope this may be of help
good luck Bob.

Click to expand...

Had the same Battery drain with my P38, basically caused by nearby Ring Doorbells, as they cause the BCM to be active. The Battery will drain overnight. Had to install cut off switch to the the battery negative terminal.

neil kirkup5 said:

Had the same Battery drain with my P38, basically caused by nearby Ring Doorbells, as they cause the BCM to be active. The Battery will drain overnight. Had to install cut off switch to the the battery negative terminal.

Click to expand...

Disconnecting the battery can bring it's own set of problems. Fitting an RF filter or the second FOB trick to isolate the RF receiver are better options.